U.S. billionaire investor Charlie Munger dies at 99

American billionaire investor Charlie Munger has died at age 99, according to a press release from Berkshire Hathaway on Tuesday.

Munger, vice chairman of Berkshire Hathaway, peacefully died Tuesday morning at a hospital in California, said the release.

Munger had been relying on a wheelchair for mobility to get around for several years, yet he had remained mentally sharp. This was evident as he answered numerous questions during this year's annual meetings of Berkshire and the Daily Journal Corp., and in recent interviews on an investing podcast and also with The Wall Street Journal and CNBC.

"Berkshire Hathaway could not have been built to its present status without Charlie's inspiration, wisdom and participation," said Warren Buffett, CEO of Berkshire Hathaway, an American multinational conglomerate holding company headquartered in Omaha, Nebraska.

Munger served as Buffett's sounding board on investments and business decisions and helped lead Berkshire for more than five decades and served as its longtime vice chairman.

The union between Munger with Buffett stands as one of the most prosperous partnerships in business history. Together, they turned Omaha, Nebraska-based Berkshire into a multi-billion-dollar conglomerate featuring numerous business units.